Step Twist Drill

FIG. 1 is a top perspective view of a step twist drill, showing my new design; FIG. 2 is a bottom perspective view thereof; FIG. 3 is a front view thereof; FIG. 4 is a rear view thereof; FIG. 5 is a left side view thereof; FIG. 6 is a right side view thereof; FIG. 7 is an enlarged plan view of the top surface; FIG. 8 is an enlarged plan view of the bottom surface; FIG. 9 is an enlarged detail view of area 9 in FIG. 1 ; and, FIG. 10 is an enlarged detail view of area 10 in FIG. 2 . The dash-dot-dash broken lines encircling the enlarged views are for annotative purposes only and form no part of the claim thereof.